These hors d’oeuvres are quick to prepare yet dressy enough for holiday entertaining. Make one or more of the bread “bases” and then choose your toppings. Figure about three to four crostini or toasts or about five pita chips per guest. You can make the bread bases a day ahead; store them in an airtight container. Many of the toppings can be made ahead too, but don’t assemble until about half an hour before serving so the bread doesn’t get soggy.